[valiant-comma]

“IIRC in 2012 the Earth missed a giant CME by one week, and had it hit Earth there would have been 80% casualties in the US...”

By casualties do you mean injuries/deaths (to people)? Do you have a source? From what I could find, it would be really bad for infrastructure, but not something that would outright kill or injure most of the population.

[sjducb]

The deaths come from lack of food and clean drinking water, caused by damage to infrastructure.

80% sounds too high and arbitrary tho.